Summary of Aircraft Accidents and Serious Incidents, and Measures

A summary of past safety troubles and measures

Fatal or serious injury of an person as a result of the operation of an aircraft, or an aircraft crash, collision or fire, as classified by the Japanese Ministry of Land, Infrastructure, Transport and Tourism (MLIT).

An incident involving circumstances indicating that there was a high probability of an accident, such as overrunning, emergency evacuation, fire or smoke inside the cabin and abnormal depressurization, encountering abnormal weather conditions, etc, as classified by the Japanese Ministry of Land, Infrastructure, Transport and Tourism (MLIT).

On December 4, 2020, Japan Airlines flight JL904 (Naha Airport bound for Tokyo International Airport) experienced left engine trouble while climing after takeoff and returned to Naha Airport. After landing, the plane underwent inspection, in which engine case damaged and fan blades missing were found on the left engine, and this case was classified as a Serious Incident by Japan Civil Aviation Bureau(JCAB), Ministry of Land, Infrastructure, Transport and Tourism(MLIT).

Investigations were conducted by the Japan Transport Safety Board, and results were announced on August 25, 2022.
According to their report, it is probable that the left engine fan blades were broken during takeoff climb, damaging the engine and causing engine parts and part of the cowling to fall off, and that the flying parts damaged the fuselage and horizontal stabilizer.
The probable cause of the broken fan blades is fatigue failure from cracks originating from nodules (small nodules stuck to the base material) that were welded to the inner surface of the hollow structure during the polishing process of the fan blades.

After the serious incident,our company implemented the following measures.
・As of March 2021, suspended operations and retired all PW4000 powered Boeing 777-200/300 aircraft